Identifying and Treating Downy Mildew on New Rose Plants

Identifying and Treating Downy Mildew on New Rose Plants

Blackish-purple spots on new leaves, especially in humid conditions, indicate downy mildew. The white residue in your photo is likely from insecticide, not the disease.

Treatment Options

1. Spray daily with 1 tablespoon baking soda in 2 quarts of water until spots disappear.
2. If persistent, apply Ortho RosePride Funginex Rose and Shrub Disease Control per label.

Fungal spores travel by wind and rain; early treatment prevents spread.